|
|
re: simple system query
9 feb 2003
wrote:
>1) you will never be able to replace the antifreeze valve for this
>type of installation. a mechanically based last resort type of freeze
>protection is required - even if it is simple a pop out frost plug or
>something.
that gives additional freeze protection. then again, so might heat tape,
thermosyphoning through a pressurized water tank below the collector,
and so on. who makes that antifreeze valve?
>2) for single tank applications the single pumped vertical
>thermosyphoning heat exchangers are absurd. (maybe this isn't what
>you are referring to) these types of heat exchangers force the
>collector operate at a temperature higher than the upper temperature
>of the tank in order to get any heat transfer.
maybe we need something more like your setup, with an external copper coil
between the drain fitting and the lower heating element hole, with the coil
in an unpressurized shallow tank.
>3) i was told the ultra reliable double walled evacuated tube heat
>pipe collectors (no metal to glass seal) would be very cheap if
>distributed in volume. something like 50cents per peak watt...
sounds like an oft-repeated pv story :-)
>i'd really like to know more about those trickle collectors. i caught
>wind of your article in solar today but didn't get a chance to read it
>through. where can i get an overview of these things?
the solar today web site has lots of references.
>are they better than normal flat plates?
they tend to be less efficient over about 90 f in wintertime, but they
might be way cheaper for large systems, about 30 cents/ft^2 for galvalume
roofing plus $1.50 for one layer of corrugated dynaglas polycarbonate.
nick
|
|
